In recent years, new imaging probes such as green fluorescent proteins, optical tweezers, single molecule FRET and super-resolution microscopy are having a profound impact on biological sciences. I will discuss our development of significantly improved, photostable rare earth nanoparticles that allow the long-term, real time tracking of proteins in live cells with millisecond time resolution and planned tracking of cells in live animals. These particles have also been used in combined SEM-cathodoluminescence nanoscale imaging. Also, recent results that have speckle-free linear and non-linear ultrasound imaging that achieves the diffraction limit will be presented.